<!doctype html>
<!--
Copyright 2016 The Chromium Authors. All rights reserved.
Use of this source code is governed by a BSD-style license that can be
found in the LICENSE file.
-->
<html>
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no">
    <meta name="mobile-web-app-capable" content="yes">
    <meta name="apple-mobile-web-app-capable" content="yes">

    <!-- Origin Trial Token, feature = WebVR (For Chrome M59+), origin = https://webvr.info, expires = 2017-10-13 -->
    <meta http-equiv="origin-trial" data-feature="WebVR (For Chrome M59+)" data-expires="2017-10-13" content="Aqw0TUvp8CwZmgIS50pM1blhzy05y7OkBeW3AQQGjer4KuKV0p13xfrRbe2bT8B1+DgRW0O3Dda0yOjcL46GBwgAAABMeyJvcmlnaW4iOiJodHRwczovL3dlYnZyLmluZm86NDQzIiwiZmVhdHVyZSI6IldlYlZSMS4xIiwiZXhwaXJ5IjoxNTA3ODU5MDE4fQ==">

    <title>06 - VR audio</title>

    <!--
      This sample demonstrates how to use WebAudio to play properly spatialized
      audio for the user's head position.
    -->

    <style>
      #webgl-canvas {
        box-sizing: border-box;
        height: 100%;
        left: 0;
        margin: 0;
        position: absolute;
        top: 0;
        width: 100%;
      }
    </style>

    <!-- This entire block in only to facilitate dynamically enabling and
    disabling the WebVR polyfill, and is not necessary for most WebVR apps.
    If you want to use the polyfill in your app, just include the js file and
    everything will work the way you want it to by default. -->
    <script>
      var WebVRConfig = {
        // Prevents the polyfill from initializing automatically.
        DEFER_INITIALIZATION: true,
        // Ensures the polyfill is always active when initialized, even if the
        // native API is available. This is probably NOT what most pages want.
        ALWAYS_APPEND_POLYFILL_DISPLAY: true,
        // Polyfill optimizations
        DIRTY_SUBMIT_FRAME_BINDINGS: true,
        BUFFER_SCALE: 0.75,
      };
    </script>
    <script src="js/third-party/webvr-polyfill.js"></script>
    <script src="js/third-party/wglu/wglu-url.js"></script>
    <script>
      // Dynamically turn the polyfill on if requested by the query args.
      if (WGLUUrl.getBool('polyfill', false)) {
        InitializeWebVRPolyfill();
      } else {
        // Shim for migration from older version of WebVR. Shouldn't be necessary for very long.
        InitializeSpecShim();
      }
    </script>
    <!-- End sample polyfill enabling logic -->

    <script src="js/third-party/gl-matrix-min.js"></script>

    <script src="js/third-party/wglu/wglu-debug-geometry.js"></script>
    <script src="js/third-party/wglu/wglu-program.js"></script>
    <script src="js/third-party/wglu/wglu-stats.js"></script>
    <script src="js/third-party/wglu/wglu-texture.js"></script>

    <script src="js/vr-cube-island.js"></script>
    <script src="js/vr-samples-util.js"></script>
    <script src="js/vr-audio-panner.js"></script>
  </head>
  <body>
    <canvas id="webgl-canvas"></canvas>
    <script>
      /* global mat4, vec3, VRAudioPanner, VRCubeIsland, WGLUDebugGeometry, WGLUStats, WGLUTextureLoader, VRSamplesUtil */
      (function () {
      "use strict";

      var PLAYER_HEIGHT = 1.65;

      var vrDisplay = null;
      var frameData = null;
      var projectionMat = mat4.create();
      var poseMat = mat4.create();
      var viewMat = mat4.create();
      var tmpMat = mat4.create();
      var vrPresentButton = null;

      // ================================================================
      // WebGL and WebAudio scene setup. This code is not WebVR specific.
      // ================================================================

      // WebGL setup.
      var gl = null;
      var cubeIsland = null;
      var stats = null;
      var debugGeom = null;

      function onContextLost( event ) {
        event.preventDefault();
        console.log( 'WebGL Context Lost.' );
        gl = null;
        cubeIsland = null;
        debugGeom = null;
        stats = null;
      }

      function onContextRestored( event ) {
        console.log( 'WebGL Context Restored.' );
        initWebGL(vrDisplay ? vrDisplay.capabilities.hasExternalDisplay : false);
      }

      var webglCanvas = document.getElementById("webgl-canvas");
      webglCanvas.addEventListener( 'webglcontextlost', onContextLost, false );
      webglCanvas.addEventListener( 'webglcontextrestored', onContextRestored, false );

      function initWebGL (preserveDrawingBuffer) {
        var glAttribs = {
          alpha: false,
          preserveDrawingBuffer: preserveDrawingBuffer
        };
        var useWebgl2 = WGLUUrl.getBool('webgl2', false);
        var contextTypes = useWebgl2 ? ["webgl2"] : ["webgl", "experimental-webgl"];
        for (var i in contextTypes) {
          gl = webglCanvas.getContext(contextTypes[i], glAttribs);
          if (gl)
            break;
        }
        if (!gl) {
          var webglType = (useWebgl2 ? "WebGL 2" : "WebGL")
          VRSamplesUtil.addError("Your browser does not support " + webglType + ".");
          return;
        }
        gl.clearColor(0.1, 0.2, 0.3, 1.0);
        gl.enable(gl.DEPTH_TEST);
        gl.enable(gl.CULL_FACE);

        var textureLoader = new WGLUTextureLoader(gl);
        var texture = textureLoader.loadTexture("media/textures/cube-sea.png");

        if (vrDisplay && vrDisplay.stageParameters &&
            vrDisplay.stageParameters.sizeX > 0 &&
            vrDisplay.stageParameters.sizeZ > 0) {
          cubeIsland = new VRCubeIsland(gl, texture, vrDisplay.stageParameters.sizeX, vrDisplay.stageParameters.sizeZ);
        } else {
          cubeIsland = new VRCubeIsland(gl, texture, 2, 2);
        }

        var enablePerformanceMonitoring = WGLUUrl.getBool(
            'enablePerformanceMonitoring', false);
        stats = new WGLUStats(gl, enablePerformanceMonitoring);
        debugGeom = new WGLUDebugGeometry(gl);

        // Wait until we have a WebGL context to resize and start rendering.
        window.addEventListener("resize", onResize, false);
        onResize();
        window.requestAnimationFrame(onAnimationFrame);
      }

      function getSoundFileData(audioFileFormat) {
        return [
          {
            name: 'drums',
            url: 'media/sound/drums.' + audioFileFormat
          }, {
            name: 'guitar',
            url: 'media/sound/guitar.' + audioFileFormat
          }, {
            name: 'perc',
            url: 'media/sound/perc.' + audioFileFormat
          }
        ];
      }

      // WebAudio setup.
      var isAudioPannerReady = false;
      var drumSource, guitarSource, percSource;

      function initAudio (buffers) {
        drumSource = VRAudioPanner.createTestSource({
          buffer: buffers.get('drums'),
          gain: 0.65,
          position: [0, PLAYER_HEIGHT, 1],
          orientation: [0, 0, 0]
        });

        guitarSource = VRAudioPanner.createTestSource({
          buffer: buffers.get('guitar'),
          gain: 0.65,
          position: [-1, PLAYER_HEIGHT, 0],
          orientation: [0, 0, 0]
        });

        percSource = VRAudioPanner.createTestSource({
          buffer: buffers.get('perc'),
          gain: 0.65,
          position: [1, PLAYER_HEIGHT, 0],
          orientation: [0, 0, 0]
        });

        var button = VRSamplesUtil.addButton("Start sound", null, null, function () {
          drumSource.start();
          guitarSource.start();
          percSource.start();
          VRSamplesUtil.removeButton(button);
        });

        isAudioPannerReady = true;
      }

      // Initiate WebGL and then Audio.
      function init (preserveDrawingBuffer) {
        initWebGL(preserveDrawingBuffer);

        // Load sound files and then initiate WebAudio.
        var infoElement = VRSamplesUtil.addInfo("Loading audio files...");
        var audioFileFormat = VRAudioPanner.isWebAudioOutdated() ? 'mp3' : 'ogg';

        VRAudioPanner.loadAudioFiles(getSoundFileData(audioFileFormat), null)
          .then(function (buffers) {
            VRSamplesUtil.makeToast(infoElement, 2000);
            initAudio(buffers);
          }, function () {
            if (audioFileFormat === "mp3") {
              VRSamplesUtil.err("Can't load audio");
              return;
            }

            // Fall back to mp3 file format
            return VRAudioPanner.loadAudioFiles(getSoundFileData("mp3"))
              .then(function(buffers) {
                VRSamplesUtil.makeToast(infoElement, 2000);
                initAudio(buffers);
              });
          });
      }


      // ================================
      // WebVR-specific code begins here.
      // ================================

      function onVRRequestPresent () {
        vrDisplay.requestPresent([{ source: webglCanvas }]).then(function () {
        }, function (err) {
          var errMsg = "requestPresent failed.";
          if (err && err.message) {
            errMsg += "<br/>" + err.message
          }
          VRSamplesUtil.addError(errMsg, 2000);
        });
      }

      function onVRExitPresent () {
        if (!vrDisplay.isPresenting)
          return;

        vrDisplay.exitPresent().then(function () {
        }, function () {
          VRSamplesUtil.addError("exitPresent failed.", 2000);
        });
      }

      function onVRPresentChange () {
        onResize();

        if (vrDisplay.isPresenting) {
          if (vrDisplay.capabilities.hasExternalDisplay) {
            VRSamplesUtil.removeButton(vrPresentButton);
            vrPresentButton = VRSamplesUtil.addButton("Exit VR", "E", "media/icons/cardboard64.png", onVRExitPresent);
          }
        } else {
          if (vrDisplay.capabilities.hasExternalDisplay) {
            VRSamplesUtil.removeButton(vrPresentButton);
            vrPresentButton = VRSamplesUtil.addButton("Enter VR", "E", "media/icons/cardboard64.png", onVRRequestPresent);
          }
        }
      }

      if (navigator.getVRDisplays) {
        frameData = new VRFrameData();

        navigator.getVRDisplays().then(function (displays) {
          if (displays.length > 0) {
            vrDisplay = displays[displays.length - 1];
            vrDisplay.depthNear = 0.1;
            vrDisplay.depthFar = 1024.0;

            init(vrDisplay.capabilities.hasExternalDisplay);

            if (vrDisplay.capabilities.canPresent)
              vrPresentButton = VRSamplesUtil.addButton("Enter VR", "E", "media/icons/cardboard64.png", onVRRequestPresent);

            // For the benefit of automated testing. Safe to ignore.
            if (vrDisplay.capabilities.canPresent && WGLUUrl.getBool('canvasClickPresents', false))
              webglCanvas.addEventListener("click", onVRRequestPresent, false);

            window.addEventListener('vrdisplaypresentchange', onVRPresentChange, false);
            window.addEventListener('vrdisplayactivate', onVRRequestPresent, false);
            window.addEventListener('vrdisplaydeactivate', onVRExitPresent, false);
          } else {
            init(false);
            VRSamplesUtil.addInfo("WebVR supported, but no VRDisplays found.", 3000);
          }
        }, function () {
          VRSamplesUtil.addError("Your browser does not support WebVR. See <a href='http://webvr.info'>webvr.info</a> for assistance.");
        });
      } else if (navigator.getVRDevices) {
        init(false);
        VRSamplesUtil.addError("Your browser supports WebVR but not the latest version. See <a href='http://webvr.info'>webvr.info</a> for more info.");
      } else {
        init(false);
        VRSamplesUtil.addError("Your browser does not support WebVR. See <a href='http://webvr.info'>webvr.info</a> for assistance.");
      }

      function onResize () {
        if (vrDisplay && vrDisplay.isPresenting) {
          var leftEye = vrDisplay.getEyeParameters("left");
          var rightEye = vrDisplay.getEyeParameters("right");

          webglCanvas.width = Math.max(leftEye.renderWidth, rightEye.renderWidth) * 2;
          webglCanvas.height = Math.max(leftEye.renderHeight, rightEye.renderHeight);
        } else {
          webglCanvas.width = webglCanvas.offsetWidth * window.devicePixelRatio;
          webglCanvas.height = webglCanvas.offsetHeight * window.devicePixelRatio;
        }
      }

      function onClick () {
        // Reset the background color to a random value
        if (gl) {
          gl.clearColor(
            Math.random() * 0.5,
            Math.random() * 0.5,
            Math.random() * 0.5, 1.0);
        }
      }

      // Register for mouse restricted events while in VR
      // (e.g. mouse no longer available on desktop 2D view)
      function onDisplayPointerRestricted() {
        if (webglCanvas && webglCanvas.requestPointerLock) {
          webglCanvas.requestPointerLock();
        }
      }

      // Register for mouse unrestricted events while in VR
      // (e.g. mouse once again available on desktop 2D view)
      function onDisplayPointerUnrestricted() {
        var lock = document.pointerLockElement;
        if (lock && lock === webglCanvas && document.exitPointerLock) {
          document.exitPointerLock();
        }
      }

      VRSamplesUtil.addVRClickListener(onClick);
      webglCanvas.addEventListener("click", onClick, false);
      window.addEventListener('vrdisplaypointerrestricted', onDisplayPointerRestricted);
      window.addEventListener('vrdisplaypointerunrestricted', onDisplayPointerUnrestricted);

      function getStandingViewMatrix (out, view) {
        if (vrDisplay.stageParameters) {
          mat4.invert(out, vrDisplay.stageParameters.sittingToStandingTransform);
          mat4.multiply(out, view, out);
        } else {
          mat4.identity(out);
          mat4.translate(out, out, [0, PLAYER_HEIGHT, 0]);
          mat4.invert(out, out);
          mat4.multiply(out, view, out);
        }
      }

      // Generate a matrix from the pose, which will represent the center of the
      // user's head.
      function getPoseMatrix (out, pose) {
        var orientation = pose.orientation;
        var position = pose.position;
        if (!orientation) { orientation = [0, 0, 0, 1]; }
        if (!position) { position = [0, 0, 0]; }

        mat4.fromRotationTranslation(tmpMat, orientation, position);
        mat4.invert(tmpMat, tmpMat);
        getStandingViewMatrix(out, tmpMat);
        mat4.invert(out, out);
      }

      function renderSceneView (projection, view) {
        cubeIsland.render(projection, view, stats);

        // Draw cubes at the position of each audio source.
        // (Red: Guitar, Green: Percussion, Blue: Drum)
        if (isAudioPannerReady) {
          debugGeom.bind(projection, view);
          debugGeom.drawCube(null, guitarSource.getPosition(), 0.1 + guitarSource.getCubeScale() * 0.5, [1, 0, 0, 1]);
          debugGeom.drawCube(null, percSource.getPosition(), 0.25 + percSource.getCubeScale() * 0.35, [0, 1, 0, 1]);
          debugGeom.drawCube(null, drumSource.getPosition(), 0.25 + drumSource.getCubeScale() * 0.35, [0, 0, 1, 1]);
        }
      }

      // For WebAudio we want to get the position of the listener and a vector
      // representing the direction they're facing. This utility function takes
      // a matrix representing the pose (not inverted) and returns WebAudio
      // compatible vectors. If you're not doing a room scale scene you can use
      // the pose position directly and use vec3.transformQuat as shown below
      // to get a direction vector for the orientation quaternion.
      var getListenerPositionDirection = (function () {
        var tmpPosition = vec3.create();
        var tmpDirection = vec3.create();
        var tmpUp = vec3.create();
        var tmpOrientation = quat.create();
        return function (poseMat) {
          mat4.getTranslation(tmpPosition, poseMat);
          mat4.getRotation(tmpOrientation, poseMat);
          vec3.transformQuat(tmpDirection, [0, 0, -1], tmpOrientation);
          vec3.transformQuat(tmpUp, [0, 1, 0], tmpOrientation);
          vec3.normalize(tmpDirection, tmpDirection);
          return {
            position: tmpPosition,
            direction: tmpDirection,
            up: tmpUp
          };
        };
      })();

      function onAnimationFrame (t) {
        // do not attempt to render if there is no available WebGL context
        if (!gl || !stats || !cubeIsland || !debugGeom) {
          return;
        }
        stats.begin();

        gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

        if (vrDisplay) {
          vrDisplay.requestAnimationFrame(onAnimationFrame);

          vrDisplay.getFrameData(frameData);

          if (vrDisplay.isPresenting) {
            gl.viewport(0, 0, webglCanvas.width * 0.5, webglCanvas.height);
            getStandingViewMatrix(viewMat, frameData.leftViewMatrix);
            renderSceneView(frameData.leftProjectionMatrix, viewMat);

            gl.viewport(webglCanvas.width * 0.5, 0, webglCanvas.width * 0.5, webglCanvas.height);
            getStandingViewMatrix(viewMat, frameData.rightViewMatrix);
            renderSceneView(frameData.rightProjectionMatrix, viewMat);

            vrDisplay.submitFrame();
          } else {
            gl.viewport(0, 0, webglCanvas.width, webglCanvas.height);
            mat4.perspective(projectionMat, Math.PI*0.4, webglCanvas.width / webglCanvas.height, 0.1, 1024.0);
            getStandingViewMatrix(viewMat, frameData.leftViewMatrix);
            renderSceneView(projectionMat, viewMat, frameData.pose);
            stats.renderOrtho();
          }

          if (isAudioPannerReady) {
            getPoseMatrix(poseMat, frameData.pose);
            // Compute the listener position/direction.
            var listener = getListenerPositionDirection(poseMat);

            // Set the listener position with WebAudio panner.
            VRAudioPanner.setListenerPosition(listener.position);
            VRAudioPanner.setListenerOrientation(listener.direction, listener.up);
          }
        } else {
          window.requestAnimationFrame(onAnimationFrame);

          // No VRDisplay found.
          gl.viewport(0, 0, webglCanvas.width, webglCanvas.height);
          mat4.perspective(projectionMat, Math.PI*0.4, webglCanvas.width / webglCanvas.height, 0.1, 1024.0);
          mat4.identity(viewMat);
          mat4.translate(viewMat, viewMat, [0, -PLAYER_HEIGHT, 0]);
          cubeIsland.render(projectionMat, viewMat, stats);

          stats.renderOrtho();
        }

        stats.end();
      }
      })();
    </script>
  </body>
</html>
